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Thread: New Sprinklers small problem

  1. #1

    Default New Sprinklers small problem

    I piped 4 zones. Three of which extend to the rear of my property. On 2 of three zones, the last sprinkler heads spray, but water shoots from the seal between the pop up part of the sprinkler head, and its casing. I replaced each head with a new one, and I am still having the same problem. Raindbird 42sa heads, rainbird valves, 1 inch poly pipe, 45 psi @ 13 gpm. I would say that I am loosing pressure but I have 1 zone with the same amount of pipe, the same length and even more heads than the ones I am having issues with. Any assistance would be greatly appreciative.

  2. #2
    DIY Senior Member chris8796's Avatar
    Join Date
    Jan 2005


    Is the 13 gpm per zone? What is the gpm at the source and the zones? Did you determine the pressure loss for each zone when designing the system?

  3. #3


    Quote Originally Posted by chris8796 View Post
    Is the 13 gpm per zone? What is the gpm at the source and the zones? Did you determine the pressure loss for each zone when designing the system?

    13gpm is the gallonage from the water source (well water to the structure) 1 zone with the problem has 9 gpm for the zone, and the 2nd zone has 11 gpm. Pressure at the hose bib of my house is 45 psi. Pressure loss was not a factor I currently had a 4 zone system in the front pushing 12 gpm per zone. I only run one zone at a time. The original 4 zones in my front yard are piped around 400 ft of 1" pipe. The two zones in my backyard im having problems with are piped around 250 ft each. I would assume i'm losing pressure after the 2nd to last head of each zone. I was just looking to see if I were missing anything before I go dig up a the last 30 feet of two zones =)

  4. #4
    Sprinkler Guy Wet_Boots's Avatar
    Join Date
    Mar 2007
    Metro NYC


    Cap off one or more heads in the trouble zones, and see what results.

  5. #5

    Default cheap heads

    If you buy heads from Hdepot or luwes they only have one thread and only last one maybe two seasons.You must buy commercial style heads

  6. #6
    DIY Junior Member PSLawnService's Avatar
    Join Date
    May 2009


    The Rainbird 42SA comes pre-nozzeled with 3 GPM. You did not say how many heads you have on each zone. With 12 GPM at the source (where the water exits the structure), you should have no more than 4 heads on a zone if the pressure is adaquate. What is happening possibly is that the last head is not coming all the way up because of low pressure. When the head is only partially up, they gush water from the seal. You lose approx 3# per 100 feet of 1" Poly pipe.
    When checking your GPM, you need a guage with 2 dials, 1. GPM, 2. PSI
    As you reduce the GPM the pressure will increase and as you increase the GPM the pressure will drop.
    Try re-nozzeling all the heads on the zones that are not working properly to 2.5 GPM or 2.0 GPM


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